the wake is deliberate input injection by privileged code, which is
exactly the kind of thing this document exists to state precisely
rather than leave to be discovered in the diff: why it must run in the
root service (uinput is root-only and the compositor holds drm master),
what it can reach (only an already-authorized _drm connection triggers
it), how narrow the trigger is (a connected-but-undriven connector,
with a self-refuting per-connector memory for the hopeless ones), the
rate bound (one wake per 20s process-wide, single winner), the device
lifetime (created and destroyed around the emit), and that a host
without /dev/uinput loses nothing it had (such a session was already
view-only).
- strict mode on the remaining two assert steps of the drm workflow
(the deb-contents assert and the glibc-floor measurement): same
masking pattern as the .so contract step fixed last round - without
set -e only the last command's status counts and the mid-script
checks were decorative. the floor extraction gets an explicit rescue
so a no-match grep still reaches the `test -n` reporter.
- the security doc states the whole accepted version window (exactly
the pinned minor with a patch floor; a NEWER minor is refused too,
because the mirrored struct layouts are only verified against the
pinned one), and the auditing section carries the command matching
its leftover-object comment.
- the uinput-missing warning literal lost the embedded space runs a
reflow had left in it (it is the sole, once-per-process diagnostic
for that failure and it read as a run-on line with gaps).
- the geometry-mismatch path in frame() hands the taken buffer back to
the recycler before erroring; dropping it made every rebuild cycle
re-allocate a scanout-sized buffer.
The one that matters: the display-cache refresh worker was the THIRD copy of
the wedged-flag hazard. catch_unwind covered only the enumeration, and
thread::spawn panics on EAGAIN after RUNNING was already swapped true, so
either path parked the flag for the process lifetime and every later refresh
- including every udev hotplug - returned early forever. Same ownership
guard as UINPUT_REFRESH_BUSY (the flag is handed back and re-taken mid-loop,
so an unconditional RAII release would clear a replacement worker's flag),
plus a fallible spawn whose failure drops the closure and releases the slot.
DRM_PROBE_IN_FLIGHT, UINPUT_REFRESH_BUSY, now this: the lesson stays
'grep for every site with the shape', and twice was not enough.
Two findings had been flagged in an earlier round and escaped the ledger:
- an unrecognized convert-output fourcc fell through to 'present as BGRA'
with a debug log, where every sibling validation in that function is a
hard error that lets the caller fall back to PipeWire. A 64bpp output
passes the stride check and encodes garbage. Hard error now.
- the trust-boundary validation constants (fourccs, MAX_DIM,
MAX_FRAME_BYTES) were declared independently on both sides of the split.
Hoisted into drm_reader, imported by the converter, so the two halves
cannot drift apart about what data they will touch.
The rest:
- the CI symbol extraction dropped any loader symbol containing a digit and
degraded to a pass-with-zero-iterations no-op if the b"..." literals were
ever refactored; digits allowed, count asserted, notice de-hardcoded.
- 'drm' in features was a substring test on the comma-joined string, so a
future drm-lease feature would have shipped the consent-bypass deb
without --drm. Exact membership now.
- the security doc claimed the deb is built on an ubuntu18.04 container;
the only deb job runs on ubuntu-24.04. The 18.04 sentence now says what
is true: 2.4.95 is an API floor, the binary floor is the build host's.
- DRM_DISPLAY_CACHE poison handling was recover-in-the-writer,
panic-in-the-readers; both readers now recover like the writer.
- the producer prewarm ran on X11 where no consumer can connect, the same
inconsistency just fixed for warm_availability. The listener still starts
(the service outlives sessions; a later Wayland login must find the
socket), only the prewarm is skipped.
The version floor I added two commits ago was one release too low.
drmtap_open_render and drmtap_convert_dmabuf are 0.4.9, but drmtap_grab_desc is
0.4.10, so a genuine 0.4.9 library passed the version gate and was then refused
by the symbol gate with a message that called it a stale or pre-release build,
which it is not. The floor is 0.4.10 now, the release where the whole split API
exists, and the test lists 0.4.9 among the rejected versions with the reason.
ExportLedger is deleted. DRM_FD_ELISION was false, so should_send_fd returned
true at its first branch and about sixty lines of eviction and epoch machinery
were unreachable, untested, in a security sensitive file. Why it was disabled
is worth keeping, so here it is: eliding the fd on an fb_id the converter has
already imported looks free, but the kernel can recycle an fb_id onto a
different buffer with identical geometry and modifier, and the exporter cannot
see the dma-buf inode that would tell the difference, so the elision can serve
a stale EGLImage. Sending it is cheap, the converter imports once per buffer and
closes the surplus fd, and libdrmtap's own cache keys on fb_id AND inode and can
only re-import when it is handed a real fd. That reasoning now lives here
instead of in dead code.
The rest:
- num_planes is clamped on the consumer before it reaches the C descriptor. The
producer normalizes it and must be root, so this is only defense in depth, but
the wire is the one place the value arrives from another process.
- warm_availability returns early on X11. Nothing there can consume a DRM
stream, and probing makes the ROOT service open DRM readers, so an X11 host
running a drm build was paying that at every startup for a path it can never
take.
- drm_cursor_id no longer clones the cursor. The cursor service polls it at
frame cadence to compare eight bytes, and a 256x256 cursor is 256 KiB.
- The premultiplied ARGB pass-through is now documented as matching the XFixes
path, since that is why it is correct rather than an oversight.
- cfg hygiene: input_service.rs uses all(target_os = "linux", feature = "drm")
like every other site, and active_uid_cached is gated with the feature too,
which also removes a dead-code warning from drm-off Linux builds.
- Nits: DrmConn is pub(crate) like its constructors, new_drm_listener is no
longer async with nothing to await, and the two anyhow! plus return Err pairs
are bail! as the codebase writes them.
- DRM_CAPTURE_SECURITY.md moves to docs/ with the other docs, and its "no
privileged child process is ever spawned" claim is corrected: an empty
helper_path is not a disable switch in the C, find_helper searches six fixed
paths and would exec one if the direct export ever failed. It is unreachable
here for two independent reasons, the root service holds CAP_SYS_ADMIN so the
direct path succeeds and the package builds no helper at all, and the paths
are root-writable only, so the accurate statement is that this package never
installs one, not that it can never happen.
- The comments that narrated the review rather than the code are rewritten to
say what the code does. One of them had also drifted: the convert context is
opened before we answer with DrmStart, not before the handshake.
Both configs build with no new warnings, 100 tests pass.
* Docs: Improve Korean translation for clarity and consistency
Corrected minor grammatical errors and improved phrasing in `CONTRIBUTING-KR.md` and `README-KR.md` for better readability and consistency.
* Docs(KR): Update Korean README/CONTRIBUTING to align with latest English versions and refine translations
* Update CONTRIBUTING.md links to point to the Chinese version
* translated with AI assistance and manual refinement
* Adapted from the official Chinese translation of the Contributor Covenant
* Improve README-ZH.md
---------
Co-authored-by: sea <api@sea.com>
Co-authored-by: Lumiphare <lumiphare@foxmail.com>
* Update CONTRIBUTING.md links to point to the Chinese version
* translated with AI assistance and manual refinement
* Adapted from the official Chinese translation of the Contributor Covenant
---------
Co-authored-by: sea <api@sea.com>
